ISO 7693:1984 PDF

Name: ISO 7693:1984 — Ferrotungsten — Determination of tungsten content — Cinchonine gravimetric method
SKU: ISO 7693:1984
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Ferrotungsten — Determination of tungsten content — Cinchonine gravimetric method

Название (английский):

ISO 7693:1984

Ferrotungsten — Determination of tungsten content — Cinchonine gravimetric method

Статус документа:: Действующий
Формат:: Электронный (PDF)
Количество страниц:: 4
Дата публикации:: 1 марта 1984 г.
Издание:: ISO IS 7693 edition 1 version 1
ICS:: 77.100

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Описание (английский):

The method is applicable to ferrotungsten having tungsten contents between 70 and 90 % (m/m). Specifies principle, reagents, apparatus, sample, procedure, expression of results and test report. It also specifies, in the annex, a spectrometric method for the determination of molybdenum which interferes with the determination.

Abstract

Похожие стандарты

Упомянутые в описании и другие стандарты ISO

Overview

ISO 7693:1984 specifies a cinchonine gravimetric method for the determination of tungsten content in ferrotungsten. The method is applicable to ferrotungsten materials with tungsten contents between 70 and 90 % (m/m). The standard defines principle, reagents, apparatus, sample preparation, step‑by‑step procedure, expression of results and requirements for the test report. An annex provides a spectrometric procedure to determine molybdenum, which can interfere with the gravimetric result.

Key topics and technical requirements

Scope: Designed for ferrotungsten alloys with 70–90% tungsten by mass.

Principle: Dissolve sample (HF, HNO3, H2SO4), evaporate, fuse residue with sodium carbonate and diboron trioxide, dissolve fused mass and precipitate tungsten as a cinchonine–a‑benzoin oxime complex; ignite to impure tungstic oxide and weigh.

Interference correction: If molybdenum is present, determine it spectrometrically (annex) and correct the tungstic oxide mass. Spectrometric measurements are made near 460 nm.

Reagents & apparatus: Standard specifies reagent grades and concentrations (HF, HNO3, HCl, H2SO4, cinchonine, a‑benzoin oxime, tin(II) chloride, ammonium thiocyanate, etc.) and typical lab equipment including spectrophotometer/spectrometer.

Sample & test portion: Powder passing 160 µm sieve prepared per ISO 3713; typical test portion ~1.000 g.

Quality controls: Includes blank and control tests, and procedures for filtration, ignition (temperature limit to avoid volatilization), fusion, and calculation.

Result expression: Tungsten content calculated from mass differences of impure tungstic oxide and residues with a conversion factor (standard gives the formula and factor).

Reporting: Test report must reference ISO 7693, identify sample, report result and method, note unusual features and any deviations from the standard procedure.

Applications and users

Who uses it: Metallurgical analysts, quality control chemists, ferroalloy producers, independent testing laboratories and regulatory bodies assessing ferrotungsten composition.

Practical uses:

Certification and quality control of ferrotungsten batches.
Incoming material inspection for steel and alloy manufacturing where tungsten content affects performance.
Dispute resolution or validation testing when compositional accuracy is required.

Benefits: Provides a standardized, reproducible gravimetric approach with defined controls and a correction path for molybdenum interference-useful where instrumental methods are not available or for confirmation of spectrometric results.

Related standards

ISO 3713 - Ferroalloys: sampling and preparation (referenced for sample preparation).

Developed by ISO/TC 132 (Ferroalloys); consult current ISO catalog for any revisions or newer analytical standards covering tungsten determination or instrumental alternatives.

Keywords: ISO 7693:1984, ferrotungsten, tungsten determination, cinchonine gravimetric method, molybdenum interference, spectrometric determination, tungsten content.

ISO 7693:1984 PDF

Abstract

Похожие стандарты

Overview

Key topics and technical requirements

Applications and users

Related standards

Технические детали

SIST ISO 3713:2000

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